Measurement Theory and Competitive Instinct
by Raziel12
Summary: Lightning and Fang are competitive about everything. Even their breasts. Serah is caught in the crossfire, and Vanille has a few suggestions.


**Measurement Theory and Competitive Instinct**

Serah was used to a certain level of idiocy from her sister and Fang. In fact, she'd come to expect it. How else could you describe two people who engaged in freaky eye sex on such a regular basis but still hadn't done so much as kiss? Yes, they were idiots – sweet, loveable idiots.

But this was a new low in what she and Vanille had dubbed the Great War of Fang and Lightning Related Unresolved Sexual Tension (GWFLRUST, pronounced gwu-ful-rust).

She and Vanille had come back from another shopping trip to find Lightning and Fang on the couch. This was not, in itself, unusual. What was unusual was that Fang was busy groping Lightning's chest – and Lightning wasn't punching her face in or returning the favour.

"Uh… are we interrupting you guys?" Serah hadn't even noticed that she'd dropped her shopping bags.

"Quiet." Fang let go of Lightning's left breast as she held up one hand for silence. "I'm concentrating."

"I can see that."

Fang stared intently at Lightning's chest before she moved one of her hands back to her own chest. Fang matched each stroke that she made to Lightning's chest with one to her own. And each of those strokes was long and lingering, delivered with a kind of languid consideration.

"I'm drunk, aren't I?" Vanille took one step forward and tripped over Serah's shopping bags. She pulled herself back to her feet without once looking away from the couch. "We must have gone drinking again, and this is some kind of vodka-induced hallucination."

Serah couldn't remember going drinking, but that would certainly explain what she was seeing. "I don't know. Maybe. But how are we hallucinating the same thing?"

"There's always a first time."

And then things got even weirder.

Fang cupped Lightning's breast again and nodded firmly. "Yep, mine are definitely bigger and firmer." Another caress provoked nothing more than a faint furrowing of Lightning's brow. "Much bigger and much firmer."

Lightning scowled and then did the absolute last thing that Serah expected – she reached out and grabbed one of Fang's breasts while holding one of her own. "Yours may be the tiniest bit bigger, but there is no way that your breasts are firmer than mine." Stroke, stroke, squeeze. "Yep, mine are much firmer.

And now Lightning and Fang were groping each other – and it wasn't even in a sexual way. Serah's mind was officially blown. And it was about to get even weirder because, honestly, that's how stuff was around Lightning and Fang – weird.

"Serah." Lightning paused in her intense scrutiny of Fang's chest to wave at her sister. "Come over here."

Serah couldn't help herself. She cringed – and hid behind Vanille. "Uh… why?"

"Don't use me as a human shield!" Vanille whispered as she tried to squirm behind Serah. "What if they ask us to join them in some kind of kinky four-way or something?"

The scariest part of what Vanille had said was not the bizarre way that Vanille's mind worked – it was the fact that she might actually be right for once.

"I need you to come over here and help us." Lightning waved again. "You can be more objective about this than either of us."

"What?" Serah squawked and flapped her arms in what was probably a combination of surprise and a desire to flee. Unfortunately, no amount of arm flapping would allow her to fly. And even if it could, all of the windows were closed. "Objective?"

"Oh no." Fang shook her head. She hadn't stopped groping Lightning. "Serah is your sister. She's going to help you cheat. If you get Serah, then I get Vanille."

"Oh sweet Maker…" Vanille grabbed Serah and clung onto her for dear life. "I was right – they are inviting us into some kind of kinky four-way!"

"Stop talking." Lightning's voice hardened. This was her big sister voice, the voice that told Serah to shut up and do exactly as she was told. "Get over here."

Serah never knew that mind control was one of Lightning's powers. But that was the only way to explain why she and Vanille walked over to couch like brain-dead zombies.

"Well?" Lightning raised one eyebrow and gestured at hers and Fang's chests. "Get to it."

"Get to what?" Serah hoped that Lightning wasn't about to ask her what she thought she was. "Lightning?"

"Are you going to check or not?" Lightning grabbed Serah by the wrist. "Come on."

Serah tried to resist – she really did – but she'd never been as strong as her sister. In less than three seconds she had one hand on one of Fang's breasts and her other hand on one of Lightning's. "I really don't think this is a good idea."

"It's a perfect idea." Lightning tightened her hold on Serah's wrist. "Now, answer the question?"

"What question?" Serah's brain had yet to catch up with recent events. She was groping her sister and Fang at the same time. There was no way that this could be real. It had to be some kind of crazy dream – a crazy dream that was probably going to turn sexual in a way that would leave her mentally scarred for the rest of her life.

"You need to check whose breasts are bigger and firmer." Fang adjusted Serah's grip on her breast. "Now get to work."

This was wrong, very wrong. But Serah's hand seemed to have a mind of its own. Why was she still touching Fang's and Lightning's breasts? And why, why, was she rubbing and stroking them? Had she taken leave of her senses? Was Vanille actually right – did Serah really have a freaky crush on her sister?

And were Fang's breasts always this big, and were Lightning's breasts always this firm –

"Ah!" Serah hurled herself away from the couch and pressed herself flat against the far wall of the living room. "Stay away!" She clawed at the air. "I am not doing this! I am not doing this!"

"I think you broke her brain." Vanille shrugged and waltzed over to the couch so that she could grope her sister and Lightning. Her fear seem to have given way to enthusiasm – perhaps at the cost of her sanity. "Besides, this can't be the first time that you've groped someone else's breasts."

"What?" Serah wrapped her arms around herself. "What are you talking about?"

"Well, you know." Vanille gave Serah a sly smile. Her hands continued their mission comparing the breasts of the two women on the couch. "Haven't you ever been curious?"

"About what?" Serah had never known that her voice could go that high. It was a miracle that the windows behind her didn't explode. It was also a miracle that she hadn't passed due to the sheer amount of blood rushing to her face as Vanille's hands slipped under first Fang's shirt and then Lightning's. "Curious about what?"

"You really don't know what I'm talking about?" Vanille giggled. She'd switched breasts. "Let's just say that I've learned to appreciate the finer points of both men and women."

It took a full three seconds for the meaning of Vanille's words to sink in. But it took her less than half a second to respond in what she felt was an appropriate manner.

"What?" The windows didn't break, but they did shake. A lot.

"And you know, Serah, I think you're really cute." Vanille grinned. "If only I could get you and Hope to come over to my apartment…"

"Not listening." Serah slapped her hands over her ears. "I am so not listening to this." But it was way, way too late. Images of her, Vanille, and Hope tangled up in the redhead's bedroom filled her mind. And to make matters worse, it wasn't long before a few other people joined her mental orgy. Was it wrong that she thought Vanille, Fang, and Lightning would look good together? Yep, it was. Way, way wrong. And the thought of being caught between Snow and Vanille shouldn't be so appealing. But it was.

Vanille turned her attention from Serah – who was doing her best impression of someone having a seizure – back to Fang and Lightning and their lovely breasts. "Hmm… I think I have to agree with Lightning here, Fang. Your breasts are little bit bigger, but hers are a shade firmer."

"Are you saying that Lightning has better breasts than me?" Fang sounded truly indignant. Clearly, the question of whose breasts were better was a matter of the utmost importance. "There is no way that Lightning has better breasts than me."

"It's not that simple." Vanille leaned in to study both breasts more intently. "There's more to a good breast than size and firmness. You also have to consider things like shape, perkiness, and texture. And even if you consider all of those things, you can't just add up the scores in each category. Oh no, measuring how good a breast is requires a more complex function than a purely additive one." Vanille nodded firmly – and accompanied that nod with a firm squeeze to the breasts she held. "In fact, it's –"

"You have an equation for how good breasts are?" Fang tilted her head to one side. "I'm your sister, and even I think that's weird."

"It was for science." Vanille shrugged. "You never know when that kind of thing might come in handy." She took her hand off Lightning's breast long enough to wave at Serah. "And for the record, Serah, yours are a solid 88/100."

That sent Serah into another fit of seizures.

"Wait… you have a number for my sister's breasts?" Lightning frowned. "What's my number then? What's Fang's?"

"It's not that simple." Vanille pursed her lips. "Proper measurement of breast goodness requires multiple measurements and a great deal of close examination."

Up against the wall, Serah had begun to froth at the mouth. Just how many times had Vanille measured, and how much close examination had their been?

"And it's not just about numbers. Sometimes it matters more who the breasts are attached to." Vanille favoured Lightning and Fang with her wisest look. "You know, Fang, I'd have thought you'd think Lightning's breasts were better because they're attached to her. It would be a lot more fun touching hers than touching yours, don't you think?"

"This has nothing to do with fun." Lightning growled. Fang still had one hand on her chest. "It's about deciding whose are better. It's for science."

"You do realise that 'it's for science' is the sort of thing I would say?" Vanille stood up and removed her hands from the breasts they'd been attached to. "Besides, if you really, really wanted to be sure, you can't be sure like this. You'd have to look at each other's bare breasts from different angles. You might even need to film them in motion."

Serah twitched. Bare breasts? Multiple angles? Filming them in motion? Vanille was like some kind of breast-measuring ninja – a breast-measuring ninja who wanted to hop into bed with her and Hope.

Lightning and Fang stared at each other, and Vanille wasn't sure if they thought her idea was the stupidest thing ever or the most brilliant thing they'd ever heard. Serah continued to rock herself back and forth against the wall.

"We're going to Hope's apartment." Vanille grabbed Serah and dragged her out the door. "Have fun, you two."

Serah came to her senses long enough to try and make a run for it. She got three steps before Vanille grabbed her. "What? Hope's apartment?"

"Relax." Vanille tossed a glance back over her shoulder. Lightning and Fang had gone back to groping each other – but in a sexual way. "We're just going to have coffee with Hope."

"Oh. Coffee? Just coffee?"

Vanille's smile sent a shiver – of fear and maybe, just a little bit, arousal – down Serah's spine. "For now…"

X X X

Serah made it halfway through coffee before she made a run for it. It wasn't Hope's fault. The blonde had been perfectly friendly. It was Vanille, and the way that she'd started running one foot up Serah's thigh before she did the same thing to Hope.

Serah didn't bother to take the car. She ran fast, and she ran far – all the way back to Lightning's house.

She found Lightning and Fang still on the couch, but with their shirts off and an ultra-high resolution camera propped up on a tripod nearby. Clearly, they were doing science. Sexy science.

And as she stumbled out of the house, locking the door behind her, she ran into Snow – sweet, loveable Snow.

"Are you okay, Serah?"

"I'm fine." Serah grabbed him with enough force to crush solid rock. "Let's just go home."

And Snow – sweet, loveable Snow – just smiled. "Sure. And by the way, I called Vanille. She and Hope are having dinner with us tonight."

X X X

**Author's Notes**

As always I neither own Final Fantasy, nor am I making any money off of this.

This chapter is dedicated to everyone who has ever wondered just how competitive Fang and Lightning are. The answer, of course, is that they are competitive to the point of being complete idiots. This chapter takes that idea and ratchets it up to eleven. This chapter is what happens when I turn off the internal filter I have that prevents me from acting like too much of an idiot. I hope you enjoyed it in all of its crack-ish, crazy goodness. I just hope I didn't mentally scar Serah too much.

I also write original fiction. My newest original story, _Durendal_, is now available on Amazon! It runs to ~80,000 words, making it the first novel-length original story that I've made available to the public! It's a coming-of-age story and a Western with elements of science fiction. If you've enjoyed my other stories, I know you'll love this one. You can find links to it in my profile.

If you're not into Westerns, you don't have to worry (although you can always have a look at _The Gunslinger and the Necromancer_ if you're after a paranormal Western with a good sense of humour). Most of my other original stuff is fantasy. If you like fantasy with plenty of atmosphere and action, check out _The Last Huntress_, I'm sure you'll love it. If you're in the mood for fantasy with a more 'old-fashioned' feel, then take a look at _The Burning Mountains_.

As always, I appreciate feedback. Reviews and comments are welcome.


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